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Finding the Fourth Proportional to 138.10, 206.36 and 99.40

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Solution

The fourth proportional to 138.10, 206.36 and 99.40 is: 148.53

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.10 : 206.36 = 99.40 : x
  2. Step 2: Convert to fraction form
    138.10/206.36 = 99.40/x
  3. Step 3: Cross multiply
    138.10x = 206.36 × 99.40
  4. Step 4: Simplify right side
    138.10x = 20,512.18
  5. Step 5: Solve for x
    x = 20,512.18/138.10
  6. Step 6: Final answer
    x = 148.53

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.